A variety of different types of weaponry which utilize discharged compressed gas to fire projectiles are known. These compressed gas powered weapons have particular use in a variety of applications including tranquilizer guns and pellet marking guns which are sometimes referred to as "paint ball guns." Generally marking guns use compressed gas to fire a relatively fragile projectile which comprises a frangible shell which is filled with a marking composition. The capsules are designed to break upon impact with a target and thereby discharge the marking material onto the target.
Such marking guns have a variety of different uses. For example, they may be employed to segregate livestock within a herd, assist in the counting of wild animals or for training of military or law enforcement personnel through simulation exercises. Likewise, they may be used by military and law enforcement personnel for crowd control. Another very popular use for such marking guns is for recreation. In particular, paint ball marking guns are used for "war games" in which participants attempt to hit other combatants with paint balls thereby marking them and eliminating them from the game.
One attribute which is extremely important to users of paint ball marking guns which are intended for such recreational war games, as well as those used for other purposes, is the rate at which the gun may be fired. Obviously, paint ball marking guns which are capable of increased firing rates offer the user a significant competitive advantage over his/her fellow combatants. One significant factor which influences the firing rate of any weapon is the type of firing arrangement that is employed. Paint ball marking guns typically may employ manual, semi-automatic and fully automatic firing arrangements. A manual firing arrangement requires appropriate manipulation of the gun before successive projectiles are fired. In contrast, a semi-automatic firing arrangement enables a projectile to fired each time the trigger is depressed, while an automatic firing arrangement will fire multiple projectiles each time the trigger is pulled.
Although fully automatic weapons may seem desirable, they suffer from various shortcomings. For example, they consume increased amounts of both ammunition and compressed air and have proven problematic, particularly due to feeding mechanism failure. Moreover, they have not achieved widespread success due to regulation prohibiting their use in many recreational settings.
One limitation on the firing rate in known weapons of this type is the fill cycle time namely, the time required to fill the firing chamber of the gun with compressed gas to the appropriate pressure. Known regulation systems have been employed that provide a regulated pressure from a compressed gas source to an air chamber to ensure that a consistent projectile velocity is achieved. One example of compressed gas powered weapons of this type may be constructed in accordance with the teachings in U.S. Pat. No. 5,280,778, assigned to assignee of the present invention. These systems regulate the pressurized gas which is supplied from the compressed gas source to the firing chamber. In this way a consistent pressure is achieved in the firing chamber for each shot, thus helping to ensure that a consistent projectile velocity is achieved for successive shots. Although this system achieves a consistent projectile velocity and enhanced accuracy of the gun, certain limitations are imposed. With the regulator system which is used in compressed gas powered weapons at this type, as the pressure in the firing chamber nears to the desired pressure, the regulator valve substantially, or at least partially closes. Thus, the gas flow into the firing chamber slows.
The result is that the regulator limits the rate at which the gun may be fired without adversely effecting the velocity of the projectile and, in turn, the accuracy of the gun. Specifically, when a user attempts to fire the gun faster than the rate at which the firing chamber is filled with compressed gas, there is insufficient time between shots for the gas in the firing chamber to reach the desired pressure. This leads to an inconsistent and lower projectile velocity which will result in diminished accuracy of the gun.